Anatomy of the pancreas. Emphasis on blood supply and lymphatic drainage.

Early diagnosis of pancreatic disease is difficult because of the position of the pancreas deep in the abdomen, where it is covered by hollow viscera, making it inaccessible for simple examination. In addition, the functional reserve of the gland is great, and over 50% of its acinar tissue must be destroyed before there is marked evidence of an effect on digestion. The stimulus to pancreatic secretion is very complicated and difficult to control because it is both humoral and neurogenic. Since the ampulla of Vater is used for both bile and pancreatic secretion and opens into the duodenum, there is a reservoir for reflux into the biliary system and the pancreas, as well as a potential route for transfer of infection. The relationship of the pancreas to the surrounding viscera, its rich blood and lymphatic supply, and its lack of complete fascial protective covering allow for the rapid and severe dissemination of malignant processes long before obvious symptoms are apparent.